The apparatus of the present invention relates to pipe plugs. More particularly, the present invention relates to an apparatus and method for isolating a segment of pipe in order to perform tasks in/or on the piping system or pipeline without being subjected to fluid pressure or hydrocarbons within the pipeline.
Industrial pipeline or piping systems require maintenance from time to time. Some maintenance procedures, such as replacing a section of pipeline or testing welds, require the isolation of a section of the pipeline from the fluids pumped through the pipeline. Such isolation is particularly important in the chemical industry because of the potential explosive or toxic nature of the fluid. In order to perform such maintenance tasks the two ends of the section of pipeline to be repaired must be sealed in order to maintain or block off fluid pressure in the line. Various known types of plugs, or the like, are placed in the pipeline and secured in place through various means.
One common such plug apparatus is disclosed in U.S. Pat. No. 5,844,127, which discloses an apparatus comprising an annular body with opposite annular faces and defining on its outer perimeter, an annular recess, a pair of bosses, a pair of resilient annular members adapted to be respectively juxtaposed between an adjacent boss and annular face; means for urging the bosses respectively against the adjacent resilient annular member so as to urge the same to frictionally engage and to seal against the internal wall of the selected pipe segment; and, means communicating through the apparatus to that plenum now defined by the recess, the resilient members and the internal wall of the pipe whereby the integrity of that pipe segment may be determined.
However, there is a need in the industry for a unitary body apparatus which would be used to isolate the end of the pipe through the use of fluid pressure, and would allow one to test the integrity of the seal between the sealing members on the apparatus so as to assure that no fluid in the pipeline, which oftentimes, is highly combustible gas, to escape into the other side of the plug in the work area.
There is also a need for the apparatus to be locked into the interior wall of the pipe to ensure that an unexpected pressure release in the pipeline will not force the apparatus out of the pipe.